DTC P0412: Secondary Air Injection System Switching Valve "A" Circuit; DTC P0415: Secondary Air Injection System Switching Valve "B" Circuit [08/2015 - 08/2017]: Description

WARNING: This page is about a different car, the 2018 Toyota Sequoia, 2017 Toyota Sequoia, and 2016 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.

The Secondary Air Injection (AIR) system consists of an air pump, the Air Switching Valve (ASV), a pressure sensor, the Air Injection Control Driver (AID) and the ECM. For a short time after cold engine starts, the AIR system pumps secondary air to the exhaust port of the cylinder head to purify the exhaust emissions. The secondary air is supplied by the air pump and is pumped to the exhaust port through the ASV.

The AID drives the ASV and the air pump according to command signals transmitted by the ECM. The pressure sensor detects the pressure in the secondary air passage when the AIR system is ON and OFF, and transmits a pressure signal to the ECM.

The AID is not only equipped to drive the pump and valve, but also with a diagnosis function to detect malfunctions in the AIR system circuit.

HINT:

As a large current is required to drive the air pump and ASV, an AID is installed to this system.

DTC No.	DTC Detection Condition	Trouble Area
P0412 P0415	After cold engine starts, all of following conditions met (1 trip detection logic): Secondary Air Injection (AIR) system not operating (air pump OFF, Air Switching Valve [ASV] OFF) Diagnostic signal from Air Injection Control Driver (AID) 40% Battery voltage 8 V or more	Open in ASV drive circuit AID ASV ECM
P0412 P0415	After cold engine starts, all of following conditions met (1 trip detection logic): Secondary Air Injection (AIR) system operating (air pump ON, Air Switching Valve [ASV] ON) Diagnostic signal from Air Injection Control Driver (AID) 40% Battery voltage 8 V or more	Short between ASV drive circuit and body ground AID ASV ECM